What is the minimal clinically important difference (MCID) for Voice Handicap Index-10 (VHI-10) in patients with unilateral vocal fold paralysis (UVFP) using anchor-based methodology?
The MCID for improvement in VHI-10 in UVFP patients is a decrease of four. This information improves understanding of patients’ response to treatment and allows comparison between different treatments. Future research should determine MCID for VHI-10 across all voice disorders.
Explore this issue:June 2018
Background: The VHI-10 is commonly used to measure patient’s perception of vocal handicap. Each statement on the 10-question instrument is rated with a 0 to 4 point Likert scale, with 0 indicating never and 4 indicating always. Higher scores are indicative that a voice problem has a more severe handicapping effect on the individual’s life than a lower score. Despite the widespread use of a patient-reported outcome (PRO) instrument in voice disorders research, a clear definition of what constitutes a clinically meaningful change in voice-related PRO, either with treatment or longitudinally over time, does not exist. The inability to identify a clinically meaningful change for patients impedes the clinicians’ ability to provide patients appropriate guidance regarding healthcare decisions about treatment, monitor disease processes over time, and measure patients’ response to treatment of their voice disorder.
The MCID is the smallest change in an outcome that is meaningful to patients. Most reports use either an anchor-based or distribution-based approach. The latter relies solely on statistical parameters to determine clinical significance, and may be less meaningful as it is not directly related to patient-derived data. The anchor-based method correlates the change in a PRO to a second measure of change (the anchor). Most anchors are a single question to assess the patient’s global rating of change. Currently, no voice-related PRO instrument has a defined MCID.
Study design: Prospective cohort questionnaire analysis.
Synopsis: Two hundred eighty-one UVFP patients completed the VHI-10 on two consecutive visits (within three months). At the follow-up visit, patients answered an 11-point Global Rating of Change Questionnaire (GRCQ) scored from −5 to +5. Relationship between the GRCQ and change in VHI-10 was quantified using analysis of variance, and MCID for the VHI-10 was determined using receiver operating characteristic (ROC) curve analysis. Overall mean VHI-10 change was −3.71 (standard deviation [SD] = 8.89) and mean GRCQ was 1.37 (SD = 2.51). Average interval between measurements was 1.73 months (SD = 0.83). Mean changes in VHI-10 scores were −7.45, −0.53, and +4.40 for patients whose GRCQ scores indicated improvement, no change, and worsening, respectively. Differences between mean scores were statistically significant (P < .001). Area under the ROC curve was 0.80, demonstrating the classification accuracy of VHI-10 change scores. A VHI-10 change of −4 was determined to be the optimal threshold that discriminated between improvement and no improvement (sensitivity and specificity 0.62 and 0.88, respectively).